Answer to Question #1:
This ECG rhythm strip shows ventricular standstill initiated by a non-conducted atrial premature beat. This is often known as ‘phase 4 block,’ or paroxysmal AV block, and was initiated by a non-conducted atrial premature beat.
Answer to Question #2:
This ECG rhythm strip shows sinus rhythm transitioning into a slightly faster accelerated idioventricular rhythm (AIVR). There appear to be at least 9 consecutive ventricular fusion beats of increasing progression. The P-R interval is foreshortening as the QRS complex gets wider. The differential diagnosis would be the so-called “concertina” effect in patients with WPW syndrome, where there is progressively increasing ventricular preexcitation. In such cases, the QRS complex would get wider at the expense of the P-R interval shortening.
This 12-lead ECG shows that every third beat is an atrial premature beat, so this is so-called atrial “trigeminy.”
Answer to Question #4:
This is piggyback heart transplant.